It is known that the efficiency of a refrigeration cycle apparatus is increased by injecting a gas phase refrigerant having an intermediate pressure into a compressor (see Patent Literature 1). With this technique, since the work of the compressor and the pressure loss of the refrigerant in an evaporator can be reduced, the coefficient of performance (COP) of the refrigeration cycle is improved.
As a compressor that can be applied to the injection technique, a rolling piston compressor provided with a plurality of vanes (blades) so as to form a first compression chamber and a second compression chamber within a cylinder has been proposed (see Patent Literature 2).
FIG. 15 is a configuration diagram of a heat pump type heating apparatus described in FIG. 3 of Patent Literature 2. A heat pump type heating apparatus 500 includes a rolling piston compressor 501, a condenser 503, an expansion mechanism 504, a gas-liquid separator 507, and an evaporator 509, and is configured to compress a gas phase refrigerant from the evaporator 509 and an intermediate pressure gas phase refrigerant separated in the gas-liquid separator 507, respectively, in the compressor 501. Vanes 525 and 535 attached to a cylinder 522 of the compressor 501 divide the space between the cylinder 522 and a rotor 523 into a main compression chamber 526 and an auxiliary compression chamber 527. The main compression chamber 526 has a suction port 526a and a discharge port 526b. The auxiliary compression chamber 527 has a suction port 527a and a discharge port 527b. The suction port 526a is connected to the evaporator 509, and the suction port 527a is connected to the gas-liquid separator 507. The discharge port 526b and the discharge port 527b are merged together and connected to the condenser 503.